Another air compressor question

[JimB]

I got a lot of great advice when I posted my previous questions so now I have one more.

I installed a HF Inline Disiccant Dryer/Filter item # 68215 between the 25 foot 3/8 hose and the 5 foot 3/8 Whip hose. The dryer/filter is definitely restricting the air flow. I know it's the filter because I removed it and reattached the 2 hoses and everything was OK. The restriction is partial as it effects the performance of the die grinder and cut off tools that use more air. I am using 90 PSI.

Did I buy the wrong dryer/filter or did I just get a defective one?

Thanks,

 

[KenV]

Or it is functioning as it is supposed to --

all the additional filters and such do restrict flow to some extent. It is called pressure drop. It takes energy to push air through the filter.

One way to decrease the pressure drop some and increase through put some is a larger filter (more area to allow air to pass).

There will still be some pressure loss and the higher the air flow the more the loss ( function of velocity squared).

 

[JimB]

Ken - the drop is significant. The die grinder slows immediately after a starting burst of speed without any load on it and the cut off tool barely runs and although I didn't try to cut anything I think it would probably stop. The brad nailer works fine but I know that consumes air differently. These are all HF tools.

 

[plantman]

How big is the tank on your compressor ??? Jim S

 

[cal91666]

Jim, I looked up the item your questioning and read through the reviews. Seems most everyone has the same issue. I did find one review that addressed the problem with a solution.........
Engineering review
We reviewed dryer for in-house use. Air must be in contact with media for 750 msec(3/4 sec) to remove water from 90% humidity to 40% ( 1.25 sec for 20%). The air flow is restricted by small orifice so that 90 psi inlet to 0 psi outlet reduces to 40% RH. This flow is not sufficient to run most tools, it is ok for painting.

DO NOT install dryer directly in-line with tool. You must use a buffer tank( we found 5 gal tank to work ok for sanders, wrenches). Run hose from compressor to dryer, then from dryer to buffer tank. From tank to tool. Remember that average air flow must be handled by buffer or not exceed 3.5 CFM or you will get very low working pressures.

Do not drill out the orifice as was mentioned in other reviews. This will indeed increase the air flow and downstream pressure; but the air will pass too quickly through the dryer media and will not be dryed(defeating the purpose of the dryer).

To get greater air flow, use several dryers in parallel. We actually use 3 dryers side by side, leading to buffer tank.

 

[JimB]

How big is the tank on your compressor ??? Jim S

It's just a pancake compressor. 6 gal, 150 PSI, HF. It is new and runs without issues.

Is it possible this filter is for something else such as to use with spray guns and not for the tools I am using?

 

[JimB]

Jim, I looked up the item your questioning and read through the reviews. Seems most everyone has the same issue. I did find one review that addressed the problem with a solution.........
Engineering review
We reviewed dryer for in-house use. Air must be in contact with media for 750 msec(3/4 sec) to remove water from 90% humidity to 40% ( 1.25 sec for 20%). The air flow is restricted by small orifice so that 90 psi inlet to 0 psi outlet reduces to 40% RH. This flow is not sufficient to run most tools, it is ok for painting.

DO NOT install dryer directly in-line with tool. You must use a buffer tank( we found 5 gal tank to work ok for sanders, wrenches). Run hose from compressor to dryer, then from dryer to buffer tank. From tank to tool. Remember that average air flow must be handled by buffer or not exceed 3.5 CFM or you will get very low working pressures.


Do not drill out the orifice as was mentioned in other reviews. This will indeed increase the air flow and downstream pressure; but the air will pass too quickly through the dryer media and will not be dryed(defeating the purpose of the dryer).

To get greater air flow, use several dryers in parallel. We actually use 3 dryers side by side, leading to buffer tank.

Sounds like it is not the right filter/dryer. I see HF has a different one that is only a few dollars more. The description sounds like it may be more for the tools I am using. Now that I have read the description better for the one I have it sounds like it is more for paint guns. That info on the packaging says "ideal for spray painting and other dry air applications". I thought 'dry air applications' was air tools but maybe not.

 

[J Michael]

Something else to consider is that the 6 gal HF compressor only puts out 2.5 CFM at 90 psi - the smallest angle die grinder (HF #32046) requires 3 CFM at 90 psi (and I would say that is the minimum on a good day - really think it is more like 4 CFM). We have a 26 gal 1.8 hp without anything in line that is supposed to put out 4 CFM at 90 psi - not sure about that rating, either. The grinder will work for about 5 minutes before it slows down to useless speed, then we have to wait for the tank to fill back up before we can use it again. Thought it was a great idea to help my son sand the bowls he was turning ... should have gone with one of the Sorby angle sander or the knockoff of it at Woodcraft.

 

[JimB]

Something else to consider is that the 6 gal HF compressor only puts out 2.5 CFM at 90 psi - the smallest angle die grinder (HF #32046) requires 3 CFM at 90 psi (and I would say that is the minimum on a good day - really think it is more like 4 CFM). We have a 26 gal 1.8 hp without anything in line that is supposed to put out 4 CFM at 90 psi - not sure about that rating, either. The grinder will work for about 5 minutes before it slows down to useless speed, then we have to wait for the tank to fill back up before we can use it again. Thought it was a great idea to help my son sand the bowls he was turning ... should have gone with one of the Sorby angle sander or the knockoff of it at Woodcraft.

Yes, it does slow after running the cut off tool for a period because the tank doesn't refill fast enough. I knew it would do that. I'm not too concerned because I will only be using it for very short periods. It's the HF 3" model and is on sale for $6.99 and you can use the 20% coupon and the 5 pack of wheels is only $2.99 on sale. The die grinder is the straight one for $9.99. The compressor almost keeps up with it. I know the compressor will limit the tools I can use.

My real concern is with the dryer/filter in place both tools do not run right. They get a second or two of full power but then slow. The cut off tool slows a lot. I just don't know if the filter/dryer is defective or if I bought the wrong filter/dryer. I think I bought the wrong one.

 

[KenV]

Jim -- if you leave an air dryer or similar device in line, you will have pressure drop. The die grinder is a marginal success and has no slack in the system. Ditch the air dryer or get a higher output compressor.

You cannot beat the laws of physics.

 

[Sabaharr]

How humid is it in New York anyway? Do you need that filter? I have only been there in winter and there was NO humidity (compared to the swamps of south east Louisiana). On your first post I didn't catch that you were referring to a pancake compressor.

 

[JimB]

Jim -- if you leave an air dryer or similar device in line, you will have pressure drop. The die grinder is a marginal success and has no slack in the system. Ditch the air dryer or get a higher output compressor.

You cannot beat the laws of physics.

I'll probably just ditch the dryer. Those laws of physics are always getting in the way .

 

[JimB]

How humid is it in New York anyway? Do you need that filter? I have only been there in winter and there was NO humidity (compared to the swamps of south east Louisiana). On your first post I didn't catch that you were referring to a pancake compressor.

I probably don't need the filter. This is my first venture into air compressors and air tools so I am learning and trying to do things right. There isn't much humidity here most of the year. There is some during the summer but my shop is in the basement and we run a de-humidifier in the basement during the summer to keep everything dry even though we don't really have a problem.

 

[cal91666]

Ditch the filter, drain the tank on your compressor regularly, and oil your tools regularly.

 

[JimB]

Ditch the filter, drain the tank on your compressor regularly, and oil your tools regularly.

That's what I did.... Thanks.